Comparison of osseointegration in piezoimplants versus cylindrical implants

BACKGROUND: Dental implants have been successful for the restoration of edentulous areas, but current techniques are inadequate in areas lacking sufficient bone volume. Piezoelectric surgery has shown encouraging effects on both osseous healing. A new wedge-shaped titanium PiezoImplant requires piezoelectric osteotomy. This study compares PiezoImplants to conventional threaded cylindrical shaped implants by microcomputed tomography and histology to assess osseointegration, tissue response, and alveolar ridge changes. METHODS: After 3 months post-extraction, 18 conventional cylindrical implants and 18 wedge-shaped PiezoImplants were placed using a split-mouth design in 3 adult mini pigs. The cylindrical implant sites were prepared for osteotomy with rotary instrumentation while the PiezoImplant sites were prepared with piezoelectric surgical inserts. One animal was sacrificed at 4, 8, and 12 weeks post operation. Quantitative µCT and histological analysis evaluated bone volume, osseointegration, and post-operative cellular events. RESULTS: The results of a multivariable linear regression model demonstrated that the PiezoImplants, arch location, and time were significant factors on higher BV/TV percentage. Bone to implant contact (BIC) analysis by high resolution microscopy and histomorphometry indicated osseointegration though intimate contact between implants and adjacent alveolar bone in both groups. The tissue response displayed no evidence of abnormal healing and the PiezoImplant was classified as a non-irritant. CONCLUSION: The combination of piezoelectric osteotomy and newly designed PiezoImplants had favorable effects on wound healing and osseointegration compared to conventional cylindrical implants. These novel wedge-shaped implants may be beneficial for narrow ridge spaces without additional ridge augmentation. Further research is needed to establish clinical validity

Reliability of Digital Dental Cast Measures as Compared to Cone-Beam Computed Tomography for Analyzing the Transverse Dimension

The purpose of this study was to assess the consistency in diagnosing the transverse dimension on cone-beam computed tomography (CBCT) images as compared to digital dental models. The study consisted of 11 patients with posterior crossbite at the level of the first molar and 17 patients with no crossbite at the level of the first molar. 13 patients were male and 15 patients were female with an overall mean age of 13.6 years. Eight linear measurements and two angular measurements were made on CBCT images of the patients and six linear measurements were made on the corresponding digital dental casts. CBCT and model measurements were compared using One-Way Analysis of Variance (ANOVA) and Pearson correlation tests were used to seek relationships between the dental and skeletal measurements on CBCT. All ratios between maxillary and corresponding mandibular measurements were larger in non-crossbite patients than in crossbite patients. The central fossa (CF) was found to be the most representative and reliable tooth measurement in judging dental and skeletal transverse dimensions. A normative CF-CF ratio was determined to be equal to or greater than 1.10 for non-crossbite patients. High correlations were found between dental and skeletal measurements for non-crossbite patients with a CF-CF ratio equal to or greater than 1.10, but were not found for crossbite patients with a CF-CF ratio less than 1.10. In conclusion, CBCT scans may not provide additional diagnostic information as compared to dental models for non-crossbite patients. However, CBCT scans may be diagnostically beneficial for crossbite patients. Further studies with a larger sample size are needed to determine the validity of this study

Prosthetic Rehabilitation Following Lateral Resection of the Mandible with a Long Cantilever Implant-Supported Fixed Prosthesis: A 3-Year Clinical Report

This clinical report describes the prosthetic management of the surgical reconstruction of a patient after mandibular resection. Complete oral rehabilitation was achieved with a maxillary complete denture and a mandibular implant-supported fixed prosthesis with a custom titanium framework and a long unilateral cantilever

Reconstruction of maxillofacial bone defects: Contemporary methods and future techniques

Reconstruction of maxillofacial continuity defects has always been a challenging tasks for the scientist and surgeons over the years. The main goal of the reconstruction of the maxillofacial region is to restore facial form, function, full rehabilitation of occlusion and articulation. A refinement in surgical technique and methods of reconstruction has improved patient’s quality of life. This manuscript reviewed exciting methods of bone reconstruction and confirms that the ideal system for reconstruction of critical size continuity defect of the jaw bones has yet to be found. Shortcoming and limitation of each method has been discussed. The author highlight recent advances on how tissue engineering which could offer biological substitute to restore, maintain, or improve oro-facial function

3D-printing techniques in a medical setting : a systematic literature review

Background: Three-dimensional (3D) printing has numerous applications and has gained much interest in the medical world. The constantly improving quality of 3D-printing applications has contributed to their increased use on patients. This paper summarizes the literature on surgical 3D-printing applications used on patients, with a focus on reported clinical and economic outcomes. Methods: Three major literature databases were screened for case series (more than three cases described in the same study) and trials of surgical applications of 3D printing in humans. Results: 227 surgical papers were analyzed and summarized using an evidence table. The papers described the use of 3D printing for surgical guides, anatomical models, and custom implants. 3D printing is used in multiple surgical domains, such as orthopedics, maxillofacial surgery, cranial surgery, and spinal surgery. In general, the advantages of 3D-printed parts are said to include reduced surgical time, improved medical outcome, and decreased radiation exposure. The costs of printing and additional scans generally increase the overall cost of the procedure. Conclusion: 3D printing is well integrated in surgical practice and research. Applications vary from anatomical models mainly intended for surgical planning to surgical guides and implants. Our research suggests that there are several advantages to 3D- printed applications, but that further research is needed to determine whether the increased intervention costs can be balanced with the observable advantages of this new technology. There is a need for a formal cost-effectiveness analysis

Radiological Society of North America (RSNA) 3D printing Special Interest Group (SIG): Guidelines for medical 3D printing and appropriateness for clinical scenarios

Este número da revista Cadernos de Estudos Sociais estava em organização quando fomos colhidos pela morte do sociólogo Ernesto Laclau. Seu falecimento em 13 de abril de 2014 surpreendeu a todos, e particularmente ao editor Joanildo Burity, que foi seu orientando de doutorado na University of Essex, Inglaterra, e que recentemente o trouxe à Fundação Joaquim Nabuco para uma palestra, permitindo que muitos pudessem dialogar com um dos grandes intelectuais latinoamericanos contemporâneos. Assim, buscamos fazer uma homenagem ao sociólogo argentino publicando uma entrevista inédita concedida durante a sua passagem pelo Recife, em 2013, encerrando essa revista com uma sessão especial sobre a sua trajetória

Comparison of piezoimplants versus conventional cylindrical implants in minipigs: stability analysis

AIM: To compare the stability of a non-cylindrical implant using piezoelectric drilling (Piezoimplant) with a cylindrical implant with conventional drilling (Nobel Biocare™). MATERIALS AND METHODS: Three adult female Gottingen miniature pigs were used for the surgical implantation. Three implants on each quadrant, randomized split-mouth design using cylindrical or non-cylindrical implants (n=36). Osteotomies were prepared using either conventional drilling technique as per manufacturer’s instruction (Nobel Biocare™) or using piezoelectric drilling (Piezotome® (P2) (Satelec Acteon, Merignac, France) with new implant prototype tips (Fraunhofer Center for Manufacturing Innovation). The minipigs were sacrificed at 4, 8 and 12-weeks. Stability tests (three per implant) using wireless Periotest® “M” were done at the start point and after euthanization. RESULTS: R-square (ANOVA) test was plotted comparing implant design, weeks 4, 8 and 12, and location (mandible and maxilla) for stability analysis. In this model, the R-square is only 0.51, which indicates only 51% of the response variability can be explained by the fitted model. Among all the 3 factors, group (experiment vs control) is the most significant one, followed by week. Location significance is the least among the three factors. CONCLUSION: In mandibular and maxillary sites in minipigs where non-cylindrical prototype implants (piezoimplant) were inserted by piezoelectric site preparation, statistically significant differences were found between control and test group stability measurements, but no differences in week (4, 8 or 12) and location among the two groups (mandible and maxilla). Stability was like the cylindrical implants. Meaning that Piezoimplants could be an alternative for narrow residual ridges.2020-03-14T00:00:00

The residual STL volume as a metric to evaluate accuracy and reproducibility of anatomic models for 3D printing: application in the validation of 3D-printable models of maxillofacial bone from reduced radiation dose CT images.

BackgroundThe effects of reduced radiation dose CT for the generation of maxillofacial bone STL models for 3D printing is currently unknown. Images of two full-face transplantation patients scanned with non-contrast 320-detector row CT were reconstructed at fractions of the acquisition radiation dose using noise simulation software and both filtered back-projection (FBP) and Adaptive Iterative Dose Reduction 3D (AIDR3D). The maxillofacial bone STL model segmented with thresholding from AIDR3D images at 100 % dose was considered the reference. For all other dose/reconstruction method combinations, a "residual STL volume" was calculated as the topologic subtraction of the STL model derived from that dataset from the reference and correlated to radiation dose.ResultsThe residual volume decreased with increasing radiation dose and was lower for AIDR3D compared to FBP reconstructions at all doses. As a fraction of the reference STL volume, the residual volume decreased from 2.9 % (20 % dose) to 1.4 % (50 % dose) in patient 1, and from 4.1 % to 1.9 %, respectively in patient 2 for AIDR3D reconstructions. For FBP reconstructions it decreased from 3.3 % (20 % dose) to 1.0 % (100 % dose) in patient 1, and from 5.5 % to 1.6 %, respectively in patient 2. Its morphology resembled a thin shell on the osseous surface with average thickness <0.1 mm.ConclusionThe residual volume, a topological difference metric of STL models of tissue depicted in DICOM images supports that reduction of CT dose by up to 80 % of the clinical acquisition in conjunction with iterative reconstruction yields maxillofacial bone models accurate for 3D printing

Flexible (Polyactive®) versus rigid (hydroxyapatite) dental implants

In a beagle dog study, the peri-implant bone changes around flexible (Polyactive®) and rigid hydroxyapatite (HA) implants were investigated radiographically by quantitative digital subtraction analysis and by assessment of marginal bone height, with the aid of a computerized method. A loss of approximately 1 mm of marginal bone height was observed for both the dense Polyactive and the HA implants, after 6 months of loading. This value appeared to be stable from 12 weeks of loading onward. Along the total length of the implant during the first 6 weeks of loading, both the flexible (dense Polyactive) and the rigid (HA) implants showed a decrease in density. However, after this 6-week period, the bone density around the implants increased, and after 18 weeks the original bone density was reached. The flexible Polyactive implants provoked less decrease in density than the rigid HA implants, although not to a statistically significant level. This finding sustains the hypothesis that flexible implant materials may transfer stresses to the surrounding bone more favorably